| (19) |
 |
|
(11) |
EP 0 040 670 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
10.02.1982 Bulletin 1982/06 |
| (43) |
Date of publication A2: |
|
02.12.1981 Bulletin 1981/48 |
| (22) |
Date of filing: 05.03.1981 |
|
|
| (84) |
Designated Contracting States: |
|
DE GB IT NL |
| (30) |
Priority: |
28.03.1980 US 135034
|
| (71) |
Applicant: PENNWALT CORPORATION |
|
() |
|
| (72) |
Inventors: |
|
- Benzinger, William Donald
()
- Robinson, Donald Nellis
()
|
|
| |
|
| (54) |
Porous vinylidene fluoride polymer membrane and process for its preparation |
(57) Vinylidene fluoride polymer ultrafiltration membranes are prepared by casting a sheet
of said polymer dissolved in a mixture of a specified solvent and a specified non-
solvent, on a smooth substrate, evaporating a portion of the solvent from the sheet,
immersing said sheet in a gelation liquid therefore, and optionally, stabilizing the
gelled sheet by heat treatment thereof. A porous vinylidene fluoride polymer membrane
having smooth, unwrinkled surfaces can be prepared in accordance with the above described
process without restraining the membrane during the evaporation and gelation steps
by utilizing triethyl phosphate as the solvent.